1. Field of the Invention
The present invention relates to a focusing device and an image pickup apparatus configured to be able to focus on a subject even when an obstruction is present in front of the subject.
2. Description of the Related Art
An image pickup apparatus is used to take images of various scenes. If an obstruction is present between the image pickup apparatus and a main subject, the main subject may be hidden behind the obstruction, preventing the desired image from being obtained. For example, Jpn. Pat. Appln. KOKAI Publication No. 2001-43458 discloses a technique to remove an obstruction by extracting a background image from the motion parallax of the obstruction if the obstruction is, for example, a person or a vehicle. Specifically, Jpn. Pat. Appln. KOKAI Publication No. 2001-43458 discloses a technique to generate image data containing the background free from the obstruction by comparing a plurality of image data obtained at different points in time with one another for each pixel, extracting pixels in which no change has been detected for a predetermined period of time, as background image data, and executing the process of extracting background image data for, for example, all the pixels in a monitor zone.